No.
The system is not set up to support mixed ticket type travel.
It’s only the fact that a tap in/out is not required inside the travelcard validity zones that means your outward journey plan is workable. Personally, I think that’s a lucky byproduct of the current implementation rather than a deliberately supported feature.
(I guess I may be doing them a disservice and it might have been introduced deliberately like this to avoid having to change the system of boundary ticketing that was already in existence.)
